&lt;p&gt;&amp;nbsp;With the&amp;nbsp;&lt;a target=&quot;_blank&quot; style=&quot;color: rgb(4, 100, 187); text-decoration: none; font-family: Tahoma, Calibri, Verdana, Geneva, sans-serif; font-size: 13px; &quot; href=&quot;http://www.ext.net/download/&quot;&gt;0.5.0 release&lt;/a&gt;&amp;nbsp;we focused a lot of attention on providing support for the UpdatePanel and now everything should be working great. Actually a few beta testers have commented that the Coolite/Ext controls work better now with the ASP.NET UpdatePanel and provide more flexibility, than the native ASP.NET AJAX controls do.&lt;/p&gt;